The invention relates to a device for cleaning an optical lens of a parking assistance camera disposed on a vehicle.
The invention further relates to a parking assistance system for a vehicle, including at least one parking assistance camera that includes at least one optical lens and is disposed on the vehicle.
Devices for cleaning an optical lens of a parking assistance camera disposed on a vehicle are known from unexamined patent applications DE 100 12 004 A1 and DE 102 25 151 A1, for example.
In contrast to driver assistance cameras that are usually disposed in the interior of a vehicle behind a windshield of the vehicle, parking assistance cameras are directly exposed to outside influences, such as weather conditions. Soiling of an optical lens of a parking assistance camera caused by the outside influences and damage to the optical lens caused by stone chips impair the image quality achievable with a parking assistance camera, which in particular makes automated image processing difficult. A further impairment of the image quality achievable with a parking assistance camera, which is frequently encountered and therefore serious, is water drops present on an optical lens of the parking assistance camera. Installing parking assistance cameras in a location having high air flow so as to remove the water drops present on an optical lens is generally difficult to implement due to design requirements.
It is the object of the invention to enable optimal cleaning of an optical lens of a parking assistance camera disposed on a vehicle, without permanently restricting an angle of view of the optical lens.
This object is achieved by a device for cleaning an optical lens of a parking assistance system, as well as by a parking assistance system having such a device, according to embodiments of the invention.
According to the invention, a device for cleaning an optical lens of a parking assistance camera disposed on a vehicle comprises: at least one inner annular body, which can be disposed on the optical lens so as to be immovable and at least partially surround the optical lens radially on the outside, and on which an annular receptacle that is developed open toward the space in question of the optical lens is disposed; and at least one outer annular body, which is disposed coaxially to the inner annular body and at least partially within the receptacle. The outer annular body is disposed so as to be axially movable relative to the inner annular body between an extended cleaning position and a retracted resting position. The outer annular body is acted upon by a restoring force in the direction of the resting position. At least one fluid chamber is disposed between the inner annular body and the outer annular body. The outer annular body is designed such that the fluid chamber is closed with respect to the surroundings of the device when the outer annular body is in the resting position. The outer annular body is designed such that the fluid chamber is open with respect to the surroundings of the device when the outer annular body is in the cleaning position, so that a fluid introduced into the fluid chamber exits the fluid chamber in the direction of the optical lens. And, at least one fluid supply element opening into the fluid chamber is disposed on the inner annular body.
For cleaning the optical lens, the outer annular body can be axially moved out of the retracted resting position thereof, in which the outer annular body does not impair the angle of view of the optical lens, relative to the inner annular body, against the restoring force acting on the outer annular body in the direction of the retracted resting position thereof, by way of a pressurized fluid acting on the fluid chamber disposed between the inner annular body and the outer annular body, and can thereby be transferred into the extended cleaning position thereof, in which the angle of view of the optical lens, and in particular of an ultra wide angle lens system, may be slightly impaired by the outer annular body. After the fluid chamber has been acted upon by a pressurized fluid, the outer annular body is transferred back into the resting position thereof, in particular automatically, due to the restoring force acting thereon in the direction of the resting position. The overall arrangement composed of the inner annular body and the outer annular body is thus telescoping.
Since the inner annular body is immovably disposed on the optical lens, which is to say is not able to carry out movements relative to the optical lens, it is possible to use the inner annular body as a part of the parking assistance camera, for example as a holder for the optical lens. The inner annular body preferably partially surrounds the optical lens radially on the outside such that the angle of view of the optical lens is not impaired by the inner annular body. The inner annular body may be circular, elliptical, or oval, and in particular it can be adapted to the shape of the optical lens. Depending on the application, a polygonal design of the inner annular body is also possible. Furthermore, the shape of the inner annular body may also deviate from an ideal ring by having a solid material reinforcement within an outer annular section.
The outer annular body disposed coaxially to the inner annular body can partially or completely surround the inner annular body radially on the outside. The dimensions of the two annular bodies can also be identical, at least in the axial direction. The outer annular body can likewise be circular, elliptical, or oval, and in particular it can be adapted to the shape of the inner annular body. Moreover, depending on the application, a polygonal design of the outer annular body is possible.
Applying a restoring force on the outer annular body in the direction of the resting position thereof can take place passively, for example, using mechanical devices, in particular at least one tension or compression spring, or passively or actively using electromagnetic devices.
The space in question of the optical lens shall be understood to mean the space in front of the optical lens in which the angle of view of the optical lens and the field of vision of the optical lens are located.
The outer annular body is designed such that the fluid chamber is closed with respect to the surroundings when the outer annular body is in the resting position thereof, so that no fluid introduced into the fluid chamber can reach the surroundings. The outer annular body may cooperate with the inner annular body for this purpose in the manner of a valve. The outer annular body is furthermore designed such that the fluid chamber is open with respect to the surroundings when the outer annular body is in the cleaning position thereof, such that fluid introduced into the fluid chamber exits the fluid chamber in the direction of the optical lens. In this way, the fluid exiting the fluid chamber, for example in the form of a fluid jet, can be directed at the optical lens for cleaning the optical lens.
At least one fluid supply element, which opens into the fluid chamber and can include at least one fluid channel, is disposed on the inner annular body. The fluid supply element can be connected in a fluid-conducting manner to a pressure-generating device for generating a pressurized fluid, wherein the fluid can be gaseous or liquid.
The two annular bodies can be made of the same material or differing materials. Metal, plastic or a composite are possible materials, for example.
According to an advantageous embodiment, the outer annular body has a U-shaped cross-section and comprises two legs and one web connecting the legs to each other, wherein the radially inner leg is shorter than the radially outer leg. If the outer annular body is in the cleaning position thereof, this embodiment causes an annular gap to be formed between the inner annular body and the outer annular body, via which the fluid chamber is open with respect to the surroundings of the device and via which the optical lens, for optimal cleaning thereof, can be acted upon by a fluid from different directions. As an alternative, the radially inner leg of the outer annular body can be designed to be approximately or equally as long as the radially outer leg, wherein at least one, and preferably two or more outlet openings are provided on the radially inner leg, via which the fluid chamber is open with respect to the surroundings of the device when the outer annular body is in the cleaning position thereof, and via which the optical lens, for optimal cleaning thereof, can be acted upon by fluid from different directions.
According to a further advantageous embodiment, at least one nozzle, which can be connected in a fluid-conducting manner to the fluid supply element or a further fluid supply element, and which is configured to direct a fluid introduced into the nozzle at the optical lens when the outer annular body is in the cleaning position thereof, is disposed on the web and/or on the radially inner leg. For cleaning the optical lens, the nozzle can be acted upon by a fluid via the fluid supply element formed on the inner annular body, or via a separate further fluid supply element. In the first case, it may be provided that the pressure loss caused by the fluid exiting the fluid chamber via the at least one nozzle is so low compared to the pressure present in the fluid chamber that the outer annular body remains in the extended cleaning position thereof while the optical lens is being cleaned. In this embodiment, it is also possible for the fluid chamber to not be open with respect to the surroundings of the device when the outer annular body is in the extended cleaning position thereof, wherein the pressure present in the fluid chamber is essentially used to displace the outer annular body from the resting position thereof into the cleaning position thereof, or to correspondingly displace the nozzles disposed on the outer annular body, while the cleaning of the optical lens is carried out solely via the nozzles. The outer annular body is only returned back into this resting position by the restoring force acting thereon in the direction of the retracted resting position when the fluid chamber is no longer acted upon by a pressurized fluid. It is also possible for two or more nozzles to be distributed around the circumference of the web and/or the radially inner leg of the outer annular body.
A parking assistance system for a vehicle is also provided, comprising at least one parking assistance camera, which includes at least one optical lens and is disposed on the vehicle, characterized by at least one device according to one of the above-mentioned embodiments or any arbitrary combination of the same.
This parking assistance system accordingly has the advantages described above with respect to the device. The parking assistance system can also have a separate corresponding device for each optical lens.
According to an advantageous embodiment, the parking assistance system includes at least one pressure-generating device for generating a pressurized fluid, which is connected in a fluid-conducting manner to the fluid supply element disposed on the inner annular body. The pressure-generating device may be a pump for this purpose. The pressure-generating device can be configured to generate a pressurized gaseous fluid, such as compressed air, and/or a liquid fluid, such as water with or without an added cleaning agent.
According to a further advantageous embodiment, the parking assistance system includes at least one fluid reservoir for a gaseous or liquid fluid, which is connected in a fluid-conducting manner to the pressure-generating device.
A further advantageous embodiment provides for the pressure-generating device to be configured to first generate a pressurized liquid fluid, and thereafter a pressurized gaseous fluid. In this way, the optical lens can first be cleaned using the liquid fluid, and thereafter the optical lens can be dried by way of the gaseous fluid, such as compressed air, so as to remove the liquid fluid from the optical lens.
It is furthermore considered advantageous if the parking assistance system comprises at least one further pressure-generating device for generating a pressurized fluid, which is connected in a fluid-conducting manner to the nozzle disposed on the outer annular body. In this way, the fluid supply element of the inner annular body and the fluid chamber alone can be used to displace the outer annular body from the resting position thereof into the cleaning position thereof, whereas the nozzle is used to clean the optical lens.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.